1. Field of the Invention
The present invention relates methods for producing a packaged tofu product, and more particularly to methods of producing and aseptically packaging tofu.
2. Description of the Related Art
Soy bean products, especially, a soy bean curd called tofu have recently become a popular high protein food for use in cooking. When tofu is used in cooking, it is desirable that the tofu have a firm texture so that the tofu does not lose its shape when it is cooked. In order to produce tofu having a firmer texture, a soy protein isolate is added to the soy bean protein. The addition of soy protein isolate increases firmness somewhat, however greater firmness often is desirable.
With the development of glucono-delta-lactone (GDL) as a food product additive, new methods for producing tofu using GDL as a coagulant have been developed. Tofu products including GDL are more easily produced in large quantities and have greater storage stability than tofu products produced by conventional processes. However, addition of too much of a coagulant, such as GDL, to increase the hardness of the tofu product, will adversely affect of the taste of the tofu product.
In order to increase the shelf life of the tofu product, packaged soy bean milk may be heat sterilized by a retort sterilization treatment. The tofu product produced by retort sterilization is called retort tofu or fresh tofu.
In order to further increase the shelf life of the tofu product, it is desirable that tofu products be aseptically packaged. Aseptic packaging of tofu increases the range of distribution which is available to the tofu producer. Processes for aseptic packaging of tofu include a step of Ultra High Temperature (UHT) treatment of the soy bean milk prior to packaging. However, such UHT treatment processes have a tendency to adversely affect the taste and/or texture of the final product when compared to non-aseptically packaged or fresh tofu.